Guys,

Just installed a new quieter muffler and am seeing some discoloration. Would you say this is due to the mixture being too rich, too lean, or is this normal?

Click to view attachment

I wouldn’t think any condition would change the appearance of the outside of the muffler unless ithe discoloration was closer to the exhaust pipe or it was rusting from the inside out. Does it rub off? Did you just paint the muffler with some high temp paint?

I think you look for discoloration at the exhaust pipe.....?

I'm running a set of the stainless -6 cyl heat exchangers from MB911. The discoloration is directly in front of where the exhaust enters the muffler.

I have tried for two years to keep my Dansk muffler "shinny" but nothing works.....except shining it all the time......oh well....looks bitchin' when it is shinny so I will keep shining it.....no coating has worked for me....your picture shows very little discoloration but since it has paint on it it will certainly deteriorate....imho....gg

That's a hot spot, most of the time on a properly running car it will actually show you where the biggest restriction is in the system.

Because the RH side has to make 90 degrees turn right there you'll see a lot of heat build up.

Don't judge engine running condition (rich/lean) by looking at discoloration of a muffler or other pipes.

Look at the spark plugs, or better yet install and use a lambda (O2) sensor and then you'll know exactly.

I don't think you can determine much from that Dee, it's probably just burning off paint

Just so you know, I'm not trying to dial in the FI by reading the muffler......I use tea leaves for that.

I've got a lamba sensor connected (obviously) and I'm watching the AFR, but just wondering because the exhaust seems so much hotter on the FI 2.7 than the carb'ed 2.0.

Never mind.....

HP makes heat
trust your gauge

is the muffler gasket leaking Dee?